It causes more long term sickness than violence, threats and sexual harassment.

A large part of the bullying in Danish workplaces will probably never come to light which, according to Prof Eriksen, simply underlines the gravity of the problem and the need for further research.

She said: “There are still many things we don’t know exactly. For example if the bullying follows the person or the workplace or both.

“But it is an expensive problem for society and for the individual, so we would like to dig deeper.”

The study, published in the journal Labour Economics, took into account factors such as the person’s previous sickness absence, attachment to the labour market, personality and the workplace’s characteristics.